In the output PDF I had some not really requested strings like "--4pc" which seem to have been ignored by pdfxmltex as input so it printed it to the output. If you pass "--stringparam passivetex.extensions 1" as additional argument to xsltproc when generating the .fo file, this output should be removed. Thanks to Justus Piater for this tip :-)

Another problem I noticed is the width of the header and footer section which seems to be more or less just half the page width. After some googling I found this mail by Gary Lawrence Murphy describing the same problem. In this thread someone also mentioned a possible solution for this, but I had no time to try it yet.

In the case of variablelists there also seem to be some fragments of the FO-element flying around. Depending on motivation and time I will also try to find a solution for this one.

Now that my docbook grows and grows I also multiplied the save_size by 10 again...